Alex Wennberg scored, and Chris Driedger made 25 saves for the Kraken (10-22-4), who are 0-7-1 in their past eight games.
The Kraken went 0-3-0 on their road trip and lost twice when leading after two periods. They led the Colorado Avalanche 3-1 in the second period and 3-2 after two before losing 4-3 Monday.
"It's obviously not the way we want it to be," Wennberg said. "Obviously we're finding ways to lose the game. We have the lead right now and again, it's a third period where we give away some goals. I mean, we've got to find something here. We've got to step up and take responsibility for what's going on.
"Right now we're not doing the job. We have no one else to blame but ourselves. There's no secret to it, it's doing the right things on the ice."
Wennberg gave the Kraken a 1-0 lead at 15:00 of the first period when he scored off the rebound of a Ryan Donato wraparound attempt in the slot.
Husso kept it 1-0 at 8:58 of the second period when he lunged to make a left-toe save on Joonas Donskoi's shorthanded bid.
"Yeah, he's a skilled guy too," Husso said of Donskoi. "As a goalie, you just need to wait what the player does and then make your move. I was just trying to hold my feet and I was lucky to make that save."
Thomas tied the game 1-1 at 1:29 of the third when he took a Brandon Saad backhand pass through the crease and beat Driedger high to his glove side.
"Great pass," Thomas said. "I think if I saw it correct, it went under the D-man's skate and under the goalie's stick, but what a pass. I had an easy job there. Pretty special pass."
Buchnevich's power-play goal at 5:30 made it 2-1, a shot from the slot after an Ivan Barbashev pass. Jordan Kyrou had the initial shot that Driedger made a save on before Barbashev got to the rebound.
"It was just a great pass by 'Buchy' and I just took a swing, and it was fortunate enough to land on 'Barby's' stick," Kyrou said. "He made a great play to 'Buchy' to put it in."
